Scalable Synthesis of 1,3,4,5-Tetraaryl Imidazolium Salts as Precursors of Sterically Demanding N-Heterocyclic Carbenes

A convenient, large-scale, and cost-efficient synthesis of 4,5-diarylsubstituted N,N-diarylimidazolium salts is described. A variety of 1,3,4,5-tetraaryl imidazolium salts with increasing electron donation and steric bulk of the N-aryl groups was synthesized in good yields. In the key step, readily available N,N′-diarylthioureas and benzoin/anisoin are coupled to give imidazole-2-thiones, followed by imidazolium salt formation by oxidative desulfurization. In this way, N,N-diarylimidazolium salts with 2-methoxy, 2-methyl, and 2-isopropyl substituents could be obtained; the synthesis of their 2-tert-butyl, 2,6-dimethyl, and 2,6-diisopropyl analogues failed.

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Pd(II) Complexes of N-Allyl Substituted N-Heterocyclic Carbenes

Zeitschrift für Naturforschung B ◽

10.1515/znb-2004-11-1223 ◽

2004 ◽

Vol 59 (11-12) ◽

pp. 1519-1523 ◽

Cited By ~ 15

Author(s):

F. Ekkehardt Hahn ◽

Beate Heidrich ◽

Thomas Lügger ◽

Tania Pape

Keyword(s):

Allyl Bromide ◽

Heterocyclic Carbenes ◽

Ethyl Bromide ◽

Imidazolium Salts ◽

Imidazolium Salt ◽

Butyl Lithium ◽

X Ray ◽

Square Planar

The unsymmetrically substituted imidazolium salt 1-ethyl-3-allyl-imidazolium bromide 1 was synthesized by treatment of imidazole with one equivalent each of n-butyl lithium and ethyl bromide followed by treatment with one equivalent of allyl bromide. The symmetrically substituted derivatives 1,3-diallyl-imidazolium bromide 2 and 1,3-bis(3-methyl-2-butenyl)-imidazolium bromide 3 were obtained from imidazole and two equivalents of allyl bromide or 4-bromo-2-methyl-2-butenyl bromide, respectively, in the presence of sodium hydrogencarbonate as a base. The imidazolium bromides 1- 3 react with Pd(OAc)2 to afford the palladium(II) dicarbene complexes trans-[PdBr2(L)2] (L = 1- ethyl-3-allyl-imidazolin-2-ylidene, 4; L = 1,3-diallyl-imidazolin-2-ylidene, 5; L = 1,3-di(3-methyl-2- butenyl)imidazolin-2-ylidene, 6) by in situ deprotonation of the imidazolium salts. The X-ray structure analyses of 4- 6 show all three complexes to be mononuclear with palladium(II) coordinated in a square-planar fashion by two carbene and two bromo ligands.

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Cost-efficient simulations of large-scale electronic structures in the standalone manycore architecture

Computer Physics Communications ◽

10.1016/j.cpc.2021.108078 ◽

2021 ◽

pp. 108078

Author(s):

Hoon Ryu ◽

Seungmin Lee

Keyword(s):

Electronic Structures ◽

Large Scale ◽

Cost Efficient

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Intramolecular Diels Alder reactions in highly organized imidazolium salt-based ionic liquid crystals

RSC Advances ◽

10.1039/c4ra11693c ◽

2015 ◽

Vol 5 (1) ◽

pp. 635-639 ◽

Cited By ~ 14

Author(s):

Tien Dat Do ◽

Andreea R. Schmitzer

Keyword(s):

Ionic Liquid ◽

Liquid Crystals ◽

Diels Alder ◽

Imidazolium Salts ◽

Imidazolium Salt ◽

New Family ◽

Ionic Liquid Crystals

This paper describes the development of a new family of ionic liquid crystals based on imidazolium salts and their applications as media for intramolecular Diels Alder reactions.

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Back Cover: Di- and Trinuclear Gold Complexes of Diphenylphosphinoethyl-Functionalised Imidazolium Salts and their N-Heterocyclic Carbenes: Synthesis and Photophysical Properties (Chem. Eur. J. 2/2015)

Chemistry - A European Journal ◽

10.1002/chem.201590004 ◽

2015 ◽

Vol 21 (2) ◽

pp. 916-916

Author(s):

Sebastian Bestgen ◽

Michael T. Gamer ◽

Sergei Lebedkin ◽

Manfred M. Kappes ◽

Peter W. Roesky

Keyword(s):

Photophysical Properties ◽

Heterocyclic Carbenes ◽

Imidazolium Salts ◽

Gold Complexes ◽

Back Cover

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Membrane-Supported Layered Coordination Polymer as an Advanced Sustainable Catalyst for Desulfurization

Molecules ◽

10.3390/molecules26092404 ◽

2021 ◽

Vol 26 (9) ◽

pp. 2404

Author(s):

Fátima Mirante ◽

Ricardo F. Mendes ◽

Rui G. Faria ◽

Luís Cunha-Silva ◽

Filipe A. Almeida Paz ◽

...

Keyword(s):

Coordination Polymer ◽

Oxidative Desulfurization ◽

Liquid System ◽

Catalytic Membrane ◽

Extraction Solvent ◽

Acrylic Glass ◽

Drying Procedures ◽

Cost Efficient ◽

Model Diesel ◽

Reaction Cycles

The application of a catalytic membrane in the oxidative desulfurization of a multicomponent model diesel formed by most refractory sulfur compounds present in fuel is reported here for the first time. The catalytic membrane was prepared by the impregnation of the active lamellar [Gd(H4nmp)(H2O)2]Cl·2H2O (UAV-59) coordination polymer (CP) into a polymethyl methacrylate (PMMA, acrylic glass) supporting membrane. The use of the catalytic membrane in the liquid–liquid system instead of a powder catalyst arises as an enormous advantage associated with the facility of catalyst handling while avoiding catalyst mass loss. The optimization of various parameters allowed to achieve a near complete desulfurization after 3 h under sustainable conditions, i.e., using an aqueous H2O2 as oxidant and an ionic liquid as extraction solvent ([BMIM]PF6, 1:0.5 ratio diesel:[BMIM]PF6). The performance of the catalytic membrane and of the powdered UAV-59 catalyst was comparable, with the advantage that the former could be recycled successfully for a higher number of desulfurization cycles without the need of washing and drying procedures between reaction cycles, turning the catalytic membrane process more cost-efficient and suitable for future industrial application.

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Time and Cost-Efficient Modeling and Generation of Large-Scale TPCC/TPCE/TPCH Workloads

Topics in Performance Evaluation, Measurement and Characterization - Lecture Notes in Computer Science ◽

10.1007/978-3-642-32627-1_11 ◽

2012 ◽

pp. 146-162 ◽

Cited By ~ 4

Author(s):

Christina Delimitrou ◽

Sriram Sankar ◽

Badriddine Khessib ◽

Kushagra Vaid ◽

Christos Kozyrakis

Keyword(s):

Large Scale ◽

Cost Efficient ◽

Efficient Modeling

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Synthesis, Characterization, and Biological Activity of Anthraquinone-Substituted Imidazolium Salts for the Treatment of Bladder Cancer

Bladder Cancer ◽

10.3233/blc-200340 ◽

2020 ◽

Vol 6 (4) ◽

pp. 471-479

Author(s):

Michael L. Stromyer ◽

David J. Weader ◽

Uttam Satyal ◽

Philip H. Abbosh ◽

Wiley J. Youngs

Keyword(s):

Bladder Cancer ◽

Cell Line ◽

Cell Lines ◽

Cancer Cell ◽

High Grade ◽

Imidazolium Salts ◽

Muscle Invasive Bladder Cancer ◽

Imidazolium Salt ◽

Muscle Invasive

BACKGROUND: Bladder cancer is one of the most common types of cancer diagnosed each year, and more than half of patients have non-muscle invasive bladder cancer (NMIBC). The standard of care for patients with high-grade NMIBC is Bacillus Calmette-Guerin (BCG). Unfortunately, multiple BCG shortages have limited access to this treatment. Available alternatives using intravesical administration of chemotherapy have some efficacy, but lack prospective validation and long-term outcomes. Development of novel intravesical therapies may provide more active alternatives to BCG for patients with high-grade NMIBC. OBJECTIVE: To develop an optimal imidazolium salt for the intravesical treatment of NMIBC and determine preliminary in vitro activity of anthraquinone-substituted imidazolium salts. METHODS: The development of the anthraquinone-substituted imidazolium salts was undertaken in an attempt to increase the potency of this class of compounds by incorporating the quinone functional group observed in the chemotherapeutics doxorubicin, valrubicin, and mitomycin. All compounds were characterized by 1H and 13C NMR spectroscopy and infrared spectroscopy. Furthermore, these imidazolium salts were tested for in vitro cytotoxicity by the Developmental Therapeutics Program (DTP) on the NCI-60 human tumor cell line screening. Additional in vitro testing was performed against diverse bladder cancer cell lines (RT112, TCCSUP, J82, and UMUC13) using CellTiter-Glo® assays and colony-forming assays. RESULTS: The NCI-60 cell line screening indicated that compound 7 had the highest activity and was concluded to be the optimal compound for further study. Using CellTiter-Glo® assays on bladder cancer cell lines, 50% growth inhibitory concentration (IC50) values were determined to range from 32–50μM after an exposure of 1 h, for compound 7. Further evaluation of the compound by colony-forming assays showed the complete inhibition of growth at 10 days post a 100μM dose of compound 7 for 1 h. CONCLUSIONS: The most active lipophilic anthraquinone imidazolium salt, compound 7, could be a viable treatment for non-muscle invasive bladder cancer as it exhibits a cell-killing effect at a 1 h time period and completely inhibits cancer regrowth in colony-forming assays.

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Real-bogus classification for the Zwicky Transient Facility using deep learning

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz2357 ◽

2019 ◽

Vol 489 (3) ◽

pp. 3582-3590 ◽

Cited By ~ 15

Author(s):

Dmitry A Duev ◽

Ashish Mahabal ◽

Frank J Masci ◽

Matthew J Graham ◽

Ben Rusholme ◽

...

Keyword(s):

Deep Learning ◽

False Positive ◽

Large Scale ◽

Moving Objects ◽

False Negative ◽

Efficient Manner ◽

Astronomical Surveys ◽

Comparable Performance ◽

Cost Efficient ◽

Initial Results

ABSTRACT Efficient automated detection of flux-transient, re-occurring flux-variable, and moving objects is increasingly important for large-scale astronomical surveys. We present braai, a convolutional-neural-network, deep-learning real/bogus classifier designed to separate genuine astrophysical events and objects from false positive, or bogus, detections in the data of the Zwicky Transient Facility (ZTF), a new robotic time-domain survey currently in operation at the Palomar Observatory in California, USA. Braai demonstrates a state-of-the-art performance as quantified by its low false negative and false positive rates. We describe the open-source software tools used internally at Caltech to archive and access ZTF’s alerts and light curves (kowalski ), and to label the data (zwickyverse). We also report the initial results of the classifier deployment on the Edge Tensor Processing Units that show comparable performance in terms of accuracy, but in a much more (cost-) efficient manner, which has significant implications for current and future surveys.

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Modeling spatiotemporal dynamics of global wetlands: comprehensive evaluation of a new sub-grid TOPMODEL parameterization and uncertainties

Biogeosciences ◽

10.5194/bg-13-1387-2016 ◽

2016 ◽

Vol 13 (5) ◽

pp. 1387-1408 ◽

Cited By ~ 21

Author(s):

Zhen Zhang ◽

Niklaus E. Zimmermann ◽

Jed O. Kaplan ◽

Benjamin Poulter

Keyword(s):

Land Surface ◽

Large Scale ◽

Comprehensive Evaluation ◽

Spatiotemporal Dynamics ◽

Fundamental Parameter ◽

Data Set ◽

Dynamic Global Vegetation Model ◽

Wetland Dynamics ◽

Cost Efficient ◽

Elevation Model

Abstract. Simulations of the spatiotemporal dynamics of wetlands are key to understanding the role of wetland biogeochemistry under past and future climate. Hydrologic inundation models, such as the TOPography-based hydrological model (TOPMODEL), are based on a fundamental parameter known as the compound topographic index (CTI) and offer a computationally cost-efficient approach to simulate wetland dynamics at global scales. However, there remains a large discrepancy in the implementations of TOPMODEL in land-surface models (LSMs) and thus their performance against observations. This study describes new improvements to TOPMODEL implementation and estimates of global wetland dynamics using the LPJ-wsl (Lund–Potsdam–Jena Wald Schnee und Landschaft version) Dynamic Global Vegetation Model (DGVM) and quantifies uncertainties by comparing three digital elevation model (DEM) products (HYDRO1k, GMTED, and HydroSHEDS) at different spatial resolution and accuracy on simulated inundation dynamics. In addition, we found that calibrating TOPMODEL with a benchmark wetland data set can help to successfully delineate the seasonal and interannual variation of wetlands, as well as improve the spatial distribution of wetlands to be consistent with inventories. The HydroSHEDS DEM, using a river-basin scheme for aggregating the CTI, shows the best accuracy for capturing the spatiotemporal dynamics of wetlands among the three DEM products. The estimate of global wetland potential/maximum is ∼ 10.3 Mkm2 (106 km2), with a mean annual maximum of ∼ 5.17 Mkm2 for 1980–2010. When integrated with wetland methane emission submodule, the uncertainty of global annual CH4 emissions from topography inputs is estimated to be 29.0 Tg yr−1. This study demonstrates the feasibility of TOPMODEL to capture spatial heterogeneity of inundation at a large scale and highlights the significance of correcting maximum wetland extent to improve modeling of interannual variations in wetland area. It additionally highlights the importance of an adequate investigation of topographic indices for simulating global wetlands and shows the opportunity to converge wetland estimates across LSMs by identifying the uncertainty associated with existing wetland products.

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